JPH10271365A - Television camera device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drastically reduce power consumption, even at an abnormally high temperature. SOLUTION: Clock signals supplied to an A/D converter 3 and a video process circuit 9 are controlled by a frequency divider ratio in a frequency divider 5, so that the signals show the same frequency as a horizontal transfer frequency of an imaging device 1, when a television camera device is normally operated and show 1/2 of the horizontal transfer frequency of the imaging device 1 or less, when an abnormal rising of surrounding temperature is detected in a temperature detecting circuit 8. In addition, the clock signals whose frequencies are divided by a frequency divider 5 are inputted to a lower bit processing circuit 11, only when the television camera device is normally operated, and an input of the clock signals to the lower bit processing circuit 11 is stopped by an operation of a switch 4, when the abnormal rise in the surrounding temperature is detected at the temperature-detecting circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television camera device, and more particularly to a low power consumption function of the television camera device.

[0002]

2. Description of the Related Art Generally, in an image pickup apparatus using a solid-state image pickup device, the reliability of the apparatus largely depends on ambient temperature conditions. However, in a television camera apparatus used outdoors such as a surveillance camera, Since the television camera device itself has a drip-proof structure or is built in a closed housing, the power consumption of the device is one of the major factors that determine the temperature conditions.

For this reason, conventionally, in an imaging apparatus using a solid-state image sensor, a technique has been proposed in which the power consumption is reduced by controlling the clock of the solid-state image sensor and the clock of a video processing circuit.

As one example, Japanese Patent Application Laid-Open No. Hei 4-273672 discloses an imaging device of a camera-integrated VTR in which power consumption is reduced by stopping a clock supplied to a video processing circuit for a certain period.

In the image pickup apparatus disclosed in Japanese Patent Application Laid-Open No. 4-273672, a clock supplied to a circuit related to picture making that does not require a blanking signal in a video processing circuit for processing a picked-up video signal. The power consumption is reduced by stopping the signal during the vertical and horizontal blanking periods of the video.

Japanese Patent Application Laid-Open No. 3-154487 discloses a digital still video camera that reduces power consumption by controlling a clock frequency in accordance with a mode setting for continuous shooting and single shooting.

In the digital still video camera disclosed in Japanese Patent Application Laid-Open No. 3-154487, 10 frames /
Power consumption is reduced by controlling the clock frequency of the video processing circuit, focusing on the difference in required signal processing time between continuous shooting in seconds and single shooting with a long imaging interval. ing.

[0008]

However, the above-mentioned conventional device has the following problems.

(1) In the power reduction technology used in the imaging apparatus disclosed in Japanese Patent Application Laid-Open No. 4-273672, the power can be reduced without lowering the resolution and gradation of the video. The power reduction rate is small, and the power cannot be reduced to such an extent that the ambient temperature is lowered at abnormally high temperatures.

For example, in the NTSC television system, the vertical blanking period is about 8% (525%) of the entire screen.
(40 of these scanning lines), and the horizontal blanking period is about 17% of the horizontal scanning period (10.9 microseconds out of 63.5 microseconds). Even if the clock can be stopped, only about 24% of the power can be reduced.

(2) In a power reduction technique used in a digital still video camera disclosed in Japanese Patent Application Laid-Open No. 3-154487, this is a method for controlling the processing time itself of one image and utilizing the characteristics of the still camera. However, in the NTSC television camera device, an image of one field in 1/60 (one frame in 1/30) must be processed. Can not.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and provides a television camera device capable of greatly reducing power consumption even at an abnormally high temperature. The purpose is to:

[0013]

According to the present invention, there is provided an image pickup device for outputting a video signal, a preamplifier for amplifying the video signal output from the image pickup device, and a clock having a constant period. A clock generator for generating and outputting a signal, an A / D converter for converting a video signal amplified by the preamplifier into a digital signal based on an input clock signal, and a A video processing circuit for processing the video signal converted to a digital signal by the A / D converter; a D / A converter for converting the video signal processed by the video processing circuit to an analog signal; An output amplifier for amplifying the video signal converted to an analog signal by the D / A converter and a video signal output terminal for outputting the video signal amplified by the output amplifier. In the television camera device,
A frequency divider that divides a clock signal output from the clock generator at a predetermined frequency division ratio, and a control circuit that outputs a control signal for setting a frequency division ratio in the frequency divider; The A / D converter and the video processing circuit operate based on a clock signal divided by the divider.

Further, the control circuit outputs a control signal such that the frequency division ratio becomes 以下 or less when a predetermined condition is satisfied.

Further, the video processing circuit includes the A /
An upper bit processing circuit for processing an upper bit video signal of the video signal converted to a digital signal by the D converter; and a lower bit of the video signal converted to a digital signal by the A / D converter And a switch for controlling the input of the clock signal divided by the frequency divider to the lower bit processing circuit based on the control signal. It is characterized by the following.

Further, the switch operates so that the input of the clock signal divided by the divider to the lower bit processing circuit is stopped when a predetermined condition is satisfied. It is characterized by the following.

A television camera device further comprising a temperature detection circuit for detecting an ambient temperature, wherein the control circuit outputs a control signal based on the temperature detected by the temperature detection circuit.

Further, the control circuit outputs a control signal such that the frequency division ratio becomes 1/2 or less when an abnormal rise in the ambient temperature is detected by the temperature detection circuit. I do.

The switch stops the input of the clock signal divided by the divider to the lower bit processing circuit when the temperature detection circuit detects an abnormal rise in the ambient temperature. It is characterized by operating as follows.

(Operation) In the present invention configured as described above, the clock signal supplied to the A / D converter and the video processing circuit is controlled by a change in ambient temperature or the like. During normal operation, the same frequency as the horizontal transfer frequency of the image sensor is set. When an abnormal rise in the ambient temperature is detected by the temperature detection circuit, the frequency is equal to or less than 1/2 of the horizontal transfer frequency of the image sensor. The frequency is controlled by the frequency division ratio in the frequency divider.

Thus, when the ambient temperature rises abnormally, the horizontal resolution of the image is reduced, but the power consumption is greatly reduced.

The input of the clock signal divided by the divider to the lower bit processing circuit is controlled by a change in ambient temperature or the like. During normal operation, the clock signal divided by the frequency divider is input to the lower bit processing circuit, and when an abnormal rise in the ambient temperature is detected by the temperature detection circuit, the frequency is divided by the frequency divider. The input of the rotated clock signal to the lower bit processing circuit is stopped by the operation of the switch.

As a result, when the ambient temperature rises abnormally, the number of processing bits of the image is reduced and the gradation is reduced, but the power consumption is greatly reduced.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a television camera device according to the present invention.

In this embodiment, as shown in FIG. 1, an image sensor 1 for outputting a video signal, a preamplifier 2 for amplifying a video signal output from the image sensor 1, a temperature detecting circuit 8 for detecting an ambient temperature, A clock generator 6 for generating and outputting a clock signal having a fixed cycle, a control circuit 7 for outputting a control signal based on the ambient temperature detected by the temperature detection circuit 8, and a control output from the control circuit 7 A frequency divider 5 that divides a clock signal output from the clock generator 6 at a frequency division ratio based on the signal, and is amplified by the preamplifier 2 based on the clock signal divided by the frequency divider 5. An A / D converter 3 for converting the video signal into a digital signal;
Based on the clock signal divided by the divider 5, A /
A video processing circuit 9 for processing a video signal converted into a digital signal by the D converter 3 and a video of a clock signal divided by the frequency divider 5 based on a control signal output from the control circuit 7 A switch 4 for switching an input to the process circuit 9; a D / A converter 12 for converting a video signal processed by the video process circuit 9 into an analog signal;
The image processing circuit 9 includes an output amplifier 13 for amplifying the video signal converted into an analog signal by the converter 12 and a video signal output terminal 14 for outputting the video signal amplified by the output amplifier 13. A / D converter 3
An upper bit processing circuit 10 for processing an upper bit video signal of the video signal converted into a digital signal at
A lower bit processing circuit 11 for processing a lower bit video signal of the video signal converted into a digital signal by the A / D converter 3 is provided. The operation of the switch 4 controls the input of the clock signal divided by the divider 5 to the lower bit processing circuit 11.

Hereinafter, the operation of the television camera device configured as described above will be described.

When a video signal is output from the image sensor 1,
In the preamplifier 2, the video signal output from the video element 1 is amplified at a predetermined amplification rate and output to the A / D converter 3.

When a clock signal having a fixed period is generated in the clock generator 6, the generated clock signal is input to the frequency divider 5, and the input clock signal is output to the frequency divider 5. The signal is divided at a predetermined dividing ratio and output.

Here, the frequency division ratio in the frequency divider 5 will be described.

The temperature detecting circuit 8 constantly detects the ambient temperature, and the control circuit 7 outputs a control signal based on the ambient temperature detected by the temperature detecting circuit 8.

Then, the frequency divider 5 sets a frequency division ratio based on the control signal output from the control circuit 7.

The clock signal output from the frequency divider 5 is
At the time of normal operation, the horizontal transfer frequency of the image sensor 1 is set to be the same frequency. When the temperature detection circuit 8 detects an abnormal increase in the ambient temperature, the horizontal transfer frequency of the image sensor 1 is set to an integer. The frequency division ratio is controlled by the control signal 7 so that the frequency becomes one-half the frequency.

The clock signal divided by the frequency divider 5 is input to the A / D converter 3 and the video processing circuit 9, respectively.

When the clock signal divided by the frequency divider 5 is input to the A / D converter 3, the video signal amplified by the preamplifier 2 is converted into a digital signal based on the input clock signal. It is converted and output to the video processing circuit 9.

Thus, when the ambient temperature rises abnormally, the power consumption can be greatly reduced, although the horizontal resolution of the image is reduced.

When a video signal converted into a digital signal by the A / D converter 3 is input to the video processing circuit 9, the higher bit video signal of the input video signal is output to the upper bit processing circuit 10. The lower bit video signal is processed in the lower bit processing circuit 11 based on the clock signal divided by the frequency divider 5.

The input of the clock signal divided by the frequency divider 5 to the lower bit processing circuit 11 is supplied to the control circuit 7.
Switch 4 that operates based on a control signal output from
Done through.

The switch 4 is normally in an ON state, whereby the clock signal divided by the frequency divider 5 is supplied to the lower bit processing circuit 11. However, when an abnormal rise in the ambient temperature is detected by the temperature detection circuit 8, the control signal output from the control circuit 7 is turned off based on the detection, whereby the clock divided by the frequency divider 5 is turned off. The supply of the signal to the lower bit processing circuit 11 is stopped.

Thus, when the ambient temperature rises abnormally, the number of processing bits of the image is reduced and the gradation is reduced, but the power consumption can be greatly reduced.

Thereafter, the video signal processed in the video process circuit 9 is converted into an analog signal by the D / A converter 12, and the video signal converted by the D / A converter 12 into an analog signal is output. Amplified by the amplifier 13,
The video signal amplified by the output amplifier 13 is output from the video signal output terminal 14.

[0042]

As described above, in the present invention,
During normal operation, the clock signal supplied to the A / D converter and the video processing circuit is set to have the same frequency as the horizontal transfer frequency of the image sensor, and an abnormal rise in the ambient temperature is detected by the temperature detection circuit. In this case, the frequency is controlled by the frequency division ratio of the frequency divider so that the frequency becomes equal to or less than の of the horizontal transfer frequency of the image sensor.
When the ambient temperature rises abnormally, the horizontal resolution of the image decreases, but the power consumption can be significantly reduced.

The input of the clock signal divided by the frequency divider to the lower bit processing circuit is performed. During normal operation, the clock signal divided by the frequency divider is input to the lower bit processing circuit. Also, when an abnormal rise in the ambient temperature is detected by the temperature detection circuit, the input of the clock signal divided by the frequency divider to the lower bit processing circuit is stopped by the operation of the switch. As a result, when the ambient temperature rises abnormally, the number of processing bits of the image decreases and the gradation decreases, but the power consumption can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a television camera device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image sensor 2 Preamplifier 3 A / D converter 4 Switch 5 Divider 6 Clock generator 7 Control circuit 8 Temperature detection circuit 9 Video processing circuit 10 Upper bit processing circuit 11 Lower bit processing circuit 12 D / A converter 13 Output Amplifier 14 Video signal output terminal

Claims (8)

[Claims] 1. An image sensor for outputting a video signal, a preamplifier for amplifying a video signal output from the image sensor, a clock generator for generating and outputting a clock signal having a fixed period, A / D for converting a video signal amplified by the preamplifier into a digital signal based on a clock signal
A converter, a video processing circuit for processing a video signal converted into a digital signal by the A / D converter based on an input clock signal, and an analog video signal processed by the video processing circuit. A D / A converter for converting the signal into a signal, an output amplifier for amplifying the video signal converted to an analog signal by the D / A converter, and a video signal output for outputting the video signal amplified by the output amplifier A frequency divider for dividing a clock signal output from the clock generator at a predetermined frequency division ratio, and a frequency divider for setting the frequency division ratio in the frequency divider. And a control circuit that outputs a control signal for the A / D converter, and wherein the A / D converter and the video processing circuit operate based on a clock signal divided by the divider. Camera device. 2. The television camera device according to claim 1, wherein the control circuit outputs a control signal such that the frequency division ratio becomes 以下 or less when a predetermined condition is satisfied. A television camera device for outputting. 3. The television camera device according to claim 2, wherein the video processing circuit processes an upper bit video signal of the video signal converted into a digital signal by the A / D converter. An upper bit processing circuit; and a lower bit processing circuit that processes a lower bit video signal of the video signal converted into a digital signal by the A / D converter. A television camera device comprising a switch for controlling an input of a clock signal divided by a frequency divider to the lower bit processing circuit. 4. The television camera device according to claim 3, wherein the switch is configured to process the lower bit of the clock signal divided by the divider when a predetermined condition is satisfied. A television camera device operable to stop input to a circuit. 5. The television camera device according to claim 2, further comprising a temperature detection circuit for detecting an ambient temperature, wherein said control circuit outputs a control signal based on the temperature detected by said temperature detection circuit. A television camera device. 6. The television camera device according to claim 5, wherein the control circuit reduces the frequency division ratio to 以下 or less when the temperature detection circuit detects an abnormal increase in ambient temperature. A television camera device which outputs a control signal as follows. 7. The television camera device according to claim 4, further comprising a temperature detection circuit for detecting an ambient temperature, wherein the control circuit outputs a control signal based on the temperature detected by the temperature detection circuit. A television camera device. 8. The television camera device according to claim 6, wherein the switch is configured to be divided by the frequency divider when an abnormal rise in ambient temperature is detected in the temperature detection circuit. A television camera device operable to stop input of a clock signal that has been passed to the lower bit processing circuit.